I have been shooting large format for a short while and reading everything I can about it when I am not taking pictures. There is a lot of talk about depth of field being shorter in 4x5 vs. smaller formats. Why is this? How does this effect everyone's large format compositions. I have spent most of my life shooting 35mm and I feel like I am still composing for large format as I would with 35mm.

Depth of field is shallower for large format because the lenses have longer focal lengths. A normal lens on 4x5 is about 150mm -- the field of view is roughly equal to that of a 50mm lens on 35mm. But the depth of field for a 150mm lens is much shallower. You can see this if, for instance, you put a 150mm lens on a 35mm camera. The field of view will be much narrower, but the depth of field is the same whether the lens is on a 4x5 or 35mm camera. This doesn't affect composition. Just look at the groundglass while stopping down the lens, and you'll see exactly what will or will not be in focus.

It gets real technical and I don't understand all of it myself. It all has to do with focal length, distance from lens to subject and, of course, f/stops. Large format, for the most part, depends on using small apertures to get the depth of field you want. View cameras with decent movements can get the depth by using front tilt, etc, at wider apertures. Again, something I won't go into here. Simple things like remembering that depth of field runs 2/3 in back of the subject and 1/3 in front are helpful. There are depth of field charts out there, too. For landscapes where there is no main subject, using small stops of f/22 and smaller will work fine.
You may want to look at the opening page at www.largeformatphotography.info
There is a lot of good information there. You can search the forum there for more. Good luck._________________Glenn